ライフサイエンスコーパス: cytoprotection

1 e a contributing factor in impaired adaptive cytoprotection.

2 by the Keap1-Nrf2 pathway, may contribute to cytoprotection.

3 g organ damage and promoting IL-10-dependent cytoprotection.

4 xide and promote cardiovascular benefits and cytoprotection.

5 phase effectively blocked the development of cytoprotection.

6 and implicate PTEN inhibition as a target in cytoprotection.

7 to explore the molecular mechanisms of this cytoprotection.

8 otentiation at other levels of signaling and cytoprotection.

9 ated the ability of these bacteria to induce cytoprotection.

10 of glycogen synthase kinase 3beta leading to cytoprotection.

11 nsport, hypoxic vasodilation, signaling, and cytoprotection.

12 they restore protein folding, thus fostering cytoprotection.

13 be an important contributor to VEGF-induced cytoprotection.

14 new strategies for anti-HCV intervention and cytoprotection.

15 ide, but also because of the benefits of HSP cytoprotection.

16 cted livers from IRI by local IL-10-mediated cytoprotection.

17 fter administration of Jo2, signifying Mcl-1 cytoprotection.

18 NOS transcription would represent a means of cytoprotection.

19 ation-resistant ARC mutant exhibits improved cytoprotection.

20 HS1-derived prostaglandins to afford gastric cytoprotection.

21 nes, some of which contribute to SF-mediated cytoprotection.

22 ict the success of pharmacologically induced cytoprotection.

23 well as p21-dependent growth suppression and cytoprotection.

24 critical mediator of IL-11- and VEGF-induced cytoprotection.

25 AR) are well characterized for their role in cytoprotection.

26 ator of HALI and a mediator of IL-11-induced cytoprotection.

27 modulates their phenotype without providing cytoprotection.

28 , and growth factors could be fundamental in cytoprotection.

29 ese two molecules in tandem providing potent cytoprotection.

30 ITIM, completely abolished PECAM-1-mediated cytoprotection.

31 D2 receptor signaling pathways mediating the cytoprotection.

32 y contribute to myoblast cell cycle exit and cytoprotection.

33 important role in the ER stress response and cytoprotection.

34 mice was used to examine its role in mucosal cytoprotection.

35 man RPTE cells before cold storage conferred cytoprotection.

36 ked CT-1-dependent NF-kappa B activation and cytoprotection.

37 expression was prerequisite for SFN-mediated cytoprotection.

38 me oxygenase-1 may serve as a basis for this cytoprotection.

39 c myocytes, may participate in MKK6-mediated cytoprotection.

40 factor-kappaB activation was not involved in cytoprotection.

41 as lower levels of heme were associated with cytoprotection.

42 effects on caspases may explain its role in cytoprotection.

43 ved in oral wound healing as well as gastric cytoprotection.

44 acting vascular reactivity, angiogenesis and cytoprotection.

45 ganoids did not benefit from the MDP-induced cytoprotection.

46 s and plays a role in tissue homeostasis and cytoprotection.

47 h concomitant downregulation of Akt-mediated cytoprotection.

48 ulting in up-regulation of ER chaperones and cytoprotection.

49 VEGFR1 led to Akt activation and facilitated cytoprotection.

50 k between TTR-Abeta binding and TTR-mediated cytoprotection.

51 y, cell development, myocardial function and cytoprotection.

52 cytotoxicity, consistent with apoE's role in cytoprotection.

53 n of oxidative metabolism and for conferring cytoprotection.

54 expression of prosurvival genes resulting in cytoprotection.

55 ctopic expression of Beclin 1 that conferred cytoprotection.

56 f ATP, which may contribute to 2-DG-mediated cytoprotection.

57 to cell adhesion and oxiredox equilibria and cytoprotection activities.

58 tometry, GB was found to display significant cytoprotection activity on three human lymphocytic cell

59 The molecular mechanism for GB cytoprotection activity was assessed via bead-based xMAP

60 The cytoprotection afforded by hepatocyte growth factor was

61 Taken together, these data demonstrated that cytoprotection afforded by IP was regulated by miR-210 i

62 ubular cells by NF-kappaB contributes to the cytoprotection afforded by osmotic diuretics.

63 l responses, including hypoxic vasodilation, cytoprotection after ischemia/reperfusion, and regulatio

64 of ER stress proteins in Ca2+ regulation and cytoprotection after treating renal epithelial cells wit

65 Complete cytoprotection against 6-OHDA toxicity and restored MOC

66 Intracellular Hsp70 provides cytoprotection against a variety of stressful stimuli, a

67 enite (As)-mediated induction of HO-1 and in cytoprotection against apoptosis.

68 CR), known for its pivotal role in mediating cytoprotection against coagulopathy, proinflammatory cyt

69 st in multiple eukaryotic species, providing cytoprotection against diverse stimuli, thus implying th

70 ediated Stc2 upregulation is responsible for cytoprotection against ectoplasmic reticulum/oxidative s

71 bservations support a prominent role for CAR cytoprotection against Fas-mediated hepatocyte injury vi

72 t to provide the evidence that HO-1-mediated cytoprotection against hepatic I/R injury depends on the

73 n abolishes DJ-1-mediated Trx1 induction and cytoprotection against hydrogen peroxide, indicating the

74 together, these data show that p21-mediated cytoprotection against hyperoxia involves regulation of

75 ptional factor which plays a crucial role in cytoprotection against inflammation, as well as oxidativ

76 for hepatic IRI, whereas HO-1 is needed for cytoprotection against innate immunity-dominated organ p

77 te to regulation of cardiac excitability and cytoprotection against ischaemia-reperfusion injury, in

78 y discovered secreted flavoprotein, provides cytoprotection against ischemic and toxic cellular injur

79 t shock protein 27 (HSP27) (or HSPB1) exerts cytoprotection against many cellular insults, including

80 s, we show that PECAM-1 provides endothelial cytoprotection against mesangial cell TGF-beta.

81 tor that critically contributes to intrinsic cytoprotection against metabolic stress.

82 Thus, NRF2 activation provides cytoprotection against numerous pathologies including ch

83 Cytoprotection against oxidant injury was determined by

84 e by HO, plays a major role in mediating the cytoprotection against oxidant-induced lung injury.

85 to dispose of heme, its activity results in cytoprotection against oxidative injury and cellular str

86 on enzymes and efflux proteins, which confer cytoprotection against oxidative stress and apoptosis in

87 her demonstrate that nuclear HO-1-associated cytoprotection against oxidative stress depends on an HO

88 tivities significantly diminished NO-induced cytoprotection against oxidative stress, whereas inhibit

89 may serve to up-regulate genes that promote cytoprotection against oxidative stress.

90 (HO-1) has previously been shown to provide cytoprotection against oxidative stress.

91 ta show that HO-1 plays an important role in cytoprotection against redox-active DEP chemicals, inclu

92 hat low-dose carbon monoxide, shown to exert cytoprotection against renal fibrosis, induces autophagy

93 ,14 prostaglandin J2 (15-d-PGJ2) and confers cytoprotection against stress stimuli and chemotherapeut

94 rgistically with other stresses and exhibits cytoprotection against subsequent exposures to other for

95 H(2)S) is emerging as an important player in cytoprotection against these stressors, which may well b

96 ytic by-product carbon monoxide (CO) confers cytoprotection against tissue and cellular injury.

97 are secreted molecules that are involved in cytoprotection against tissue damage and the immune resp

98 nsistent with a model whereby MKP-1 provides cytoprotection against UV-induced apoptosis by inhibitin

99 age-related macular degeneration, including cytoprotection and angiogenesis.

100 atients with MDS with the unique approach of cytoprotection and anticytokine therapies as well as the

101 se-1 (HO-1) and -2 play an important role in cytoprotection and are physiologic regulators of heme-de

102 Hsp70 is a proximal sensor for Hsf1-mediated cytoprotection and can discriminate between two distinct

103 naling pathway is well-known for its role in cytoprotection and cell survival, we tested the hypothes

104 paradoxical ability of heat shock to induce cytoprotection and cytotoxicity the heat shock paradox.

105 hed new light on the mechanism of amifostine cytoprotection and encourage clinical research with this

106 that are claimed to play essential roles in cytoprotection and epithelial repair within the gastroin

107 e p38beta MAPK mediated the effects of CO on cytoprotection and Hsp70 regulation.

108 tudy confirms the clinical relevance of HO-1 cytoprotection and identifies SIRT1-mediated autophagy p

109 es highlight the potential of TPs in retinal cytoprotection and implicate PTEN inhibition as a target

110 determines cellular fate by regulating both cytoprotection and induction of apoptosis based on the m

111 is an oncogene that functions in cancer cell cytoprotection and mitosis.

112 ortance of cytoplasmic signaling pathways in cytoprotection and mutagenesis.

113 eed, cytokines and growth factors can induce cytoprotection and neovascularization.

114 Initially, UPR signaling aims at cytoprotection and restoration of ER homeostasis; that f

115 probiotics continue to unravel mechanisms of cytoprotection and suggest that approaches utilizing mic

116 n of various genes involved in inflammation, cytoprotection, and carcinogenesis.

117 n of various genes involved in inflammation, cytoprotection, and carcinogenesis.

118 ) phosphorylation/inactivation, resulting in cytoprotection, and that interference with these events

119 fects on tissue ischemia/reperfusion injury, cytoprotection, and vasodilation.

120 The underlying mechanism of this cytoprotection appeared to imply activation of the Akt p

121 signaling mechanisms underlying CO-mediated cytoprotection are not well understood.

122 ent mechanisms modulated by MMF that lead to cytoprotection are unknown.

123 Cytoprotection assays in ARPE-19 cells that were overexp

124 To determine whether TPs confer in vivo cytoprotection, BALB/c mice were pretreated with CDDO-TF

125 elopment, nutrition, host microbial balance, cytoprotection, barrier function, innate immunity, and i

126 t only that BVR advances the role of HO-1 in cytoprotection but also affords cytoprotection independe

127 This confers not only cell-autonomous cytoprotection but also paracrine establishment of a str

128 l phenotype, modulation of inflammation, and cytoprotection, but little is known about its regulation

129 Here we report cytoprotection by a cell-impermeant derivative of strych

130 Cytoprotection by activated protein C (aPC) after ischem

131 pecific amino acid substitution in mediating cytoprotection by AGS ATP5G1.

132 Cytoprotection by ATP depletion preconditioning or A(1)

133 reased caspase activities, Smac release, and cytoprotection by caspase inhibitors.

134 Cytoprotection by CD40 involves activation of protective

135 Cytoprotection by EPO was completely abolished by cotrea

136 ant cytoprotective effects and also provides cytoprotection by facilitating iron extrusion from cells

137 Cytoprotection by glucose but not acidosis was associate

138 mulation, suggesting a possible mechanism of cytoprotection by GSK-3beta inhibitors.

139 THBS1 confers cytoprotection by maintaining expression of mesencephali

140 in SOD activity but not GSH, indicating that cytoprotection by Mn-SOD overexpression is related to mi

141 Cytoprotection by NF-kappaB involves the activation of p

142 These findings extend prior evidence for cytoprotection by Ngb and suggest both direct (parenchym

143 d characterized signaling factors triggering cytoprotection by NO.

144 CI, Yan et al. describe a novel mechanism of cytoprotection by p40, a soluble product of Lactobacillu

145 Cytoprotection by PDGF-BB was dependent upon Hedgehog (H

146 The strategy provides robust cytoprotection by restoring redox and protein homeostasi

147 Cytoprotection by SF/HGF in vitro was also inhibited by

148 uter surface of plasma membranes may mediate cytoprotection by strychnine and glycine.

149 the predominant signaling cascade mediating cytoprotection by the D2 receptor involves c-Src/EGFR tr

150 Cytoprotection by these two hsp is thought to result fro

151 cally, constitutively active FOXO3 conferred cytoprotection by transcriptionally downregulating CSRP1

152 We show that cytoprotection by VEGF C can be related to induction of

153 re assessed to evaluate the cytotoxicity and cytoprotection capacity against ROS/RNS on BAEC.

154 urvival mechanisms (inhibition of apoptosis, cytoprotection, cell growth, and stimulation of translat

155 These results suggest that the cytoprotection conferred by alpha7 nicotinic receptor ag

156 tent these changes in iNOS contribute to the cytoprotection conferred by CO, it is fascinating that i

157 mation, reduce oxidative stress, and provide cytoprotection, consequent to lipid raft disorganization

158 We observed that cytoprotection correlated with the affinity of the compo

159 IGF-1-mediated cytoprotection correlated with the wortmannin-sensitive

160 erves to illustrate that EPO can offer novel cytoprotection during ischemic vascular injury through d

161 type-1 IFN pathway in the mechanism of HO-1 cytoprotection during liver IRI.

162 erved ARE sequences by which JunD may confer cytoprotection during oxidative stress.

163 gs demonstrate that H(2)S may be of value in cytoprotection during the evolution of myocardial infarc

164 Cytoprotection during the heat shock response is a compl

165 sis that bilirubin is a key mediator of HO-1 cytoprotection, employing a rat model of endotoxemia.

166 cts on EPC function and how IGFBP-3 mediates cytoprotection following vascular injury.

167 dy is the first to report that Tregs provide cytoprotection for CEnCs through secretion of IL-10, ind

168 tored EGF receptor-->Akt1 axis signaling and cytoprotection from a phosphoinositide 3-kinase-dependen

169 The genes that mediate cytoprotection from doxorubicin belong to multiple pathw

170 To determine the mechanisms that mediate cytoprotection from doxorubicin, we have screened the co

171 ype (WT) mice; and (2) responsible for liver cytoprotection from IR, because neutralization of IL-10

172 in cAMP, activation of protein kinase A, and cytoprotection from oxidative injury.

173 and CDDO-trifluoroethylamide [-TFEA]) confer cytoprotection from oxidative- and photooxidative-induce

174 ced lipid trafficking are more important for cytoprotection from strain injury than are the innate me

175 Genetic modification of the liver to induce cytoprotection has potential applications to prevent I/R

176 pathways, inhibits inflammation and provides cytoprotection; hence, we hypothesized that STC1 will in

177 ptosis (IAP), growth (VEGF, H11 kinase), and cytoprotection (HSP70, HIF-1alpha, GLUT1).

178 These anti-inflammatory properties result in cytoprotection in a broad spectrum of graft injury exper

179 chemia-reperfusion organ damage and promoted cytoprotection in a clinically relevant model of extende

180 antiapoptotic properties of CO confer potent cytoprotection in a rat model of lung transplantation.

181 WT), whereas ASK1 silencing (siRNA) promoted cytoprotection in cold-stressed and damage-prone CC1-def

182 sulfide cystamine have demonstrated dramatic cytoprotection in experimental models where antioxidants

183 r data identify a mechanism for MMF-mediated cytoprotection in human astrocytes that functions in an

184 The mechanisms of interleukin-11 (IL-11) cytoprotection in intestinal epithelial injury are large

185 implicated in the development of injury and cytoprotection in kidney transplantation.

186 llular Ca2+ regulation, MAPK activation, and cytoprotection in LLC-PK1 renal epithelial cells in an a

187 eficiency effectively abolished pioglitazone cytoprotection in mouse cerebral vascular endothelial ce

188 ing enhanced activity resulting in increased cytoprotection in myocardial reperfusion injury.

189 ure to oxidative stress can evoke endogenous cytoprotection in NPCs.

190 , events that may represent the target of NO cytoprotection in preconditioning.

191 orted to mediate hyperosmotic stress-induced cytoprotection in renal medullary cells.

192 ERK activation and cytoprotection in response to either ligand were attenua

193 y, we elucidated a mechanism for eIF2alpha-P cytoprotection in response to UVB in human keratinocytes

194 heme oxygenase-1 (HO-1)-accompanied hepatic cytoprotection in Stat4 KO recipients.

195 the heat shock response as a means to confer cytoprotection in the clinical setting.

196 epigenetic changes in malignant cells afford cytoprotection in the face of genomic instability, oncog

197 , metabolized in remote organs, and mediates cytoprotection in the setting of I/R injury.

198 -induced HO-1 is an important contributor to cytoprotection in this in vivo model of acute lung injur

199 ne, a general regulator of cell division and cytoprotection in tumors.

200 iquitous protein that is reported to provide cytoprotection in various cell types and tissues.

201 ignaling mechanism through which aPC conveys cytoprotection in various cell types remain incompletely

202 AMP-PKA signaling in hepatic homeostasis and cytoprotection in vivo.

203 ts, to specifically show that PINK1 mediates cytoprotection in wild-type and NLRP3(-/-) mice.

204 e of HO-1 in cytoprotection but also affords cytoprotection independent of heme degradation.

205 by which Bcl-2 may mediate endothelial cell cytoprotection independently of cytochrome c release: (a

206 ciations with other molecules and that Bcl-2 cytoprotection involves mechanisms that prevent Bax olig

207 ngs elucidate the NOD2-mediated mechanism of cytoprotection involving the clearance of the lethal exc

208 This observed cytoprotection is associated with an inhibition of myoca

209 This cytoprotection is associated with increases in mitochond

210 ranscriptional profiling suggested that such cytoprotection is connected with the induction of genes

211 We conclude that Tfp-induced cytoprotection is due in part to ERK-dependent modificat

212 thelia, we hypothesized that IL-11-conferred cytoprotection is mediated by inducible hsps.

213 They also demonstrate that the cytoprotection is mediated via a PI3K/Akt-dependent and

214 In contrast, no cytoprotection is offered by inhibitors of secreted phos

215 The mechanism(s) by which HO-1 provides this cytoprotection is poorly understood.

216 IL-11-induced cytoprotection is protein synthesis dependent and may de

217 ent feature of carbon monoxide (CO)-mediated cytoprotection is the suppression of inflammation and ce

218 One potential mechanism whereby CO affords cytoprotection is through its anti-apoptotic properties.

219 Strikingly, the induction of cytoprotection is tightly linked to the pathways that in

220 Although the mechanism of nitrite-mediated cytoprotection is unknown, NO is a mediator of the ische

221 models, where these thiol agents demonstrate cytoprotection, is the generation of cytotoxic aldehydes

222 els, and mitochondrial connexin 43 (Cx43) in cytoprotection, it is not clear how these signaling modu

223 crease in endogenous H2S production provides cytoprotection, its chronic increase such as in cystathi

224 has been recognized as a master regulator of cytoprotection, its functional significance remains to b

225 Thus, EspZ-dependent host cell cytoprotection likely prevents epithelial cell death and

226 signaling complexes underlying aPC-mediated cytoprotection may allow the design of cell type specifi

227 We hypothesized that the FN mediated cytoprotection may be in part due to perturbations in ce

228 location of the K(ATP) channels relevant to cytoprotection may be on the mitochondrial inner membran

229 The cytoprotection may result from the elimination of heme a

230 elucidation of the mechanisms of HSP-induced cytoprotection may result in therapeutic strategies that

231 r, the multifaceted targets of HO-1-mediated cytoprotection may simultaneously benefit both local gra

232 ment of other cytoprotective proteins in the cytoprotection mechanism.

233 pathway may be more selective as compared to cytoprotection mediated by other IAPs.

234 17beta-E(2)-mediated cytoprotection occurred through the preservation of mito

235 and to elucidate the mechanism by which this cytoprotection occurs.

236 Cytoprotection of brain endothelium by APC in vitro requ

237 ability may be responsible for the observed cytoprotection of different cell types.

238 ular endothelial growth factor(VEGF)-induced cytoprotection of endothelial cell monolayers correlated

239 vel role for membrane-anchored HB-EGF in the cytoprotection of epithelial cells.

240 ediated gene transfer of EPO would result in cytoprotection of human pancreatic islets in culture and

241 ing agents, increasing evidence for EPO/EPOR cytoprotection of ischemically injured tissues, and pote

242 inated manner and play a pivotal role in the cytoprotection of neuronal cells.

243 We investigated here the mechanism of cytoprotection of nitric oxide (*NO) in bovine aortic en

244 cGMP-dependent kinase inhibition blocked the cytoprotection of NO.

245 sed as the basis for selective p53-dependent cytoprotection of nonmalignant cells.

246 imultaneously induce antiapoptotic genes for cytoprotection of RPTEC.

247 ial molecular events in MSC exosome mediated cytoprotection of stressed cardiomyocytes.

248 a suggest that greater mechanoprotection and cytoprotection of the lung are conferred during PLV with

249 Thus, the cytoprotection of the vector-infected cells with antiapo

250 ironment, the production of NO may result in cytoprotection or cytotoxicity.

251 her potential therapeutic agents directed at cytoprotection or reduction of fibrosis are under invest

252 annel modulators-did not affect NO-dependent cytoprotection or reperfusion injury.

253 ful transition of cell immobilization from a cytoprotection point of view to that of a cell-instructi

254 r isoflurane anesthesia might confer in vivo cytoprotection, possibly by causing renal tubular inorga

255 g the mechanisms of cell death induction and cytoprotection relevant for glaucoma pathogenesis.

256 ation, the mediator or mediators of adaptive cytoprotection remain poorly understood.

257 The cytoprotection rendered by Stat4 disruption remains HO-1

258 APC's cytoprotection requires its receptor, endothelial cell p

259 Consistent with growth suppression and cytoprotection requiring different levels of p21, hypero

260 -deficient dominant-negative Akt1 eliminates cytoprotection, suggesting that activation of Akt1 is ne

261 f hsp25 by IL-11 confers epithelial-specific cytoprotection that is independent of phosphorylation-de

262 unctions, ranging from hormone secretion and cytoprotection to appetite control and hair growth.

263 Stc2 gene expression, which in turn confers cytoprotection to liver cells exposed to chemical insult

264 Thus, MAGE-B2 provides cytoprotection to maintain mammalian spermatogenesis, a

265 Similarly, ESAs did not reproducibly provide cytoprotection to neuronal, renal, or cardiac cells.

266 endothelial cells, in its ability to confer cytoprotection to proapoptotic stimuli, and in maintaini

267 Hsp31 relocalizes to mitochondria to provide cytoprotection to the organelle under oxidative stress c

268 mechanisms by which MT participates in this cytoprotection, transgenic mice containing high levels o

269 nance of mitochondrial function and provides cytoprotection under conditions that induce increased mi

270 p38 MAPK pathways may regulate the level of cytoprotection versus apoptosis and is a new mechanism t

271 une regulatory mechanism, rather than direct cytoprotection via mitochondria permeability transition

272 h, transient mild light illumination elicits cytoprotection via mitochondrial preconditioning.

273 ovides mechanistic insight into MMF-mediated cytoprotection via NRF2, OSGIN1, and P53 in human CNS-de

274 described as an inducible protein capable of cytoprotection via radical scavenging and apoptosis prev

275 After rewarming, significant cytoprotection was also observed in grafts from animals

276 Comparable cytoprotection was also seen in experiments comparing wi

277 This cytoprotection was associated with Akt phosphorylation a

278 Live cell imaging established that cytoprotection was associated with suppression of (phosp

279 DNA-damaging agents and that HGF/SF-mediated cytoprotection was associated with up-regulation of the

280 A role for Hsp90 mobilization in cytoprotection was confirmed by the finding that brief h

281 To verify that the proximate cause of hemin cytoprotection was due to HO-1 induction, we transiently

282 The 17beta-E(2)-mediated cytoprotection was inhibited by ER antagonists ICI (ERal

283 d necrotic killing after 6 hours to 26%, but cytoprotection was lost after 16 hours.

284 GTx-822 mediated cytoprotection was mediated through induction of both ge

285 The extent of Bcl-2-mediated cytoprotection was not significantly different for heter

286 Hepatocyte growth factor cytoprotection was prevented by pretreatment with the ph

287 Cytoprotection was quantified by MTT assay.

288 duced in GECs expressing iPLA2gamma, and the cytoprotection was reversed by dominant-negative ATF6.

289 " reactions, but how this reaction conferred cytoprotection was unclear.

290 ase in hepatic NO metabolites could modulate cytoprotection, we subjected CS-eNOS-Tg mice to hepatic

291 oth UDP and LTD4-mediated ERK activation and cytoprotection were absent in mBMMCs lacking CysLT1R and

292 e A(1) and A(2a) adenosine receptor-mediated cytoprotection were also dependent on G(i/o) proteins an

293 however, N-acetylcysteine was ineffective in cytoprotection when added after TBH-induced ROS formatio

294 stimulated cell proliferation and conferred cytoprotection when cells were challenged with cisplatin

295 f tear fluid threefold significantly reduced cytoprotection, while bacteriostatic activity prevailed

296 InsP3-1 to provide sufficient autophagy for cytoprotection, while prolonged exposure to propofol ind

297 derived factor and DHA uncovered synergistic cytoprotection with concomitant NPD1 synthesis when cell

298 Harnessing the mechanisms of cytoprotection with HSP27 may lead to new therapies for

299 Despite cytoprotection with low (less than fivefold) HO activity

300 r, maturing erythroblasts required Spi2A for cytoprotection, with iron and reactive oxygen species as